Referring to FIG. 1, a conventional foldable umbrella 10 is shown to include an elongate handle 18, a ferrule 17, a runner 19, a plurality of rib assemblies, and a plurality of stretcher assemblies.
As illustrated, the handle 18 has an upper end 180, a lower end 181 and a middle portion 182 between the upper and lower ends 180,181. The ferrule 17 is fixed on the upper end 180 of the handle 18. The runner 19 is sleeved slidably on the middle portion 182 of the handle 18. Each of the rib assemblies includes a first rib 11, a second rib 12, and a third rib 13. The first rib 11 has a first proximate end 110 connected pivotally to the ferrule 17, a first distal end 111 opposite to the first proximate end 110, and a first pivot 112 between the first proximate and first distal ends 110,111. The second rib 12 has second proximate and second distal ends 121,122 opposite to each other relative to the ferrule 17, and a second pivot 123 between the second proximate and second distal ends 121,122 and disposed adjacent to the second proximate end 121. The second pivot 123 is connected pivotally to the first distal end 111 of the first rib 11.
Each of the stretcher assemblies includes a stretcher 14, a first connecting member 15 and a second connecting member 16. The stretcher 14 has a third proximate end 141 connected pivotally to the runner 19, and a third distal end 142 connected pivotally to the first pivot 112 of the first rib 11 of a corresponding one of the rib assemblies. The first connecting member 15 is a non-flexible elongate member having a fourth proximate end 150 connected pivotally to the stretcher 14 adjacent to the third distal end 142, and a fourth distal end 151 connected pivotally to the second proximate end 121 of the second rib 12 of the corresponding one of the rib assemblies. The third rib 13 has fifth proximate and fifth distal ends 131,132 opposite to each other relative to the ferrule 17, and a third pivot 133 between the fifth proximate and fifth distal ends 131, 132 and disposed adjacent to the fifth proximate end 131. The third pivot 133 is connected pivotally to the second distal end 122 of the second rib 12. The second connecting member 16 is a flexible elongate member and has a sixth proximate end 161 connected pivotally to the first rib 11 adjacent to the first distal end 111, and a sixth distal end 162 connected pivotally to the fifth proximate end 131 of the third rib 13 of the corresponding one of the rib assemblies. Movement of the runner 19 along the handle 18 will cause the first, second and third ribs 11,12, 13 of the rib assemblies to move between spread-out and collapsed positions. The second connecting member 16 supports the third rib 13 of the corresponding one of the rib assemblies in the spread-out state.
However, a drawback of the aforesaid conventional foldable umbrella arises in the presence of relatively strong wind. It is noted that the second connecting members 16 are flexible members which can lead to ease of deformation of the rib assemblies.
In U.S. patent Ser. No. 09/407,153 by the applicant, there is disclosed a foldable umbrella that includes an elongate handle, a ferrule fixed on an upper end of the handle, and a runner sleeved slidably on a middle portion of the handle. Each of a plurality of rib assemblies includes a first rib having an elongate abutment wall with opposite longitudinal edges, two opposite side walls that extend downwardly and respectively from the longitudinal edges of the abutment wall, a first proximate end connected pivotally to the ferrule, a first distal end opposite to the first proximate end, and a first pivot between the first proximate and first distal ends. A second rib has second proximate and second distal ends opposite to each other relative to the ferrule, and a second pivot between the second proximate and second distal ends and disposed adjacent to the second proximate end. The second pivot is connected pivotally to the first distal end of the first rib. Each of a plurality of stretcher assemblies includes a stretcher having a third proximate end connected pivotally to the runner, and a third distal end connected pivotally to the first pivot of the first rib of a corresponding one of the rib assemblies. A flexible and elongate connecting member has a fourth proximate end connected pivotally to the stretcher adjacent to the third distal end, a fourth distal end connected pivotally to the second proximate end of the second rib of the corresponding one of the rib assemblies, and an intermediate portion between the fourth proximate and fourth distal ends. The connecting member has a length sufficient to cause the intermediate portion to flex so as to extend between the side walls and abut against the abutment wall of the first rib of the corresponding one of the rib assemblies when the first and second ribs of the corresponding one of the rib assemblies are generally aligned with one another in a spread-out state of the corresponding one of the rib assemblies.
The intermediate portion of the connecting member is straightened when an external force applied on the second rib of the corresponding one of the rib assemblies causes the second rib of the corresponding one of the rib assemblies to pivot upwardly relative to the first rib about the second pivot in the spread-out state of the corresponding one of the rib assemblies to avoid deformation of the second rib.